A hybrid microphone array post-filter in a diffuse noise field

In this paper, a hybrid post-filter for microphone arrays with the assumption of a diffuse noise field is proposed to suppress correlated as well as uncorrelated noise. In the proposed post-filter, a modified Zelinski post-filter, which is estimated using the signals on the microphone pairs on which noises are uncorrelated by considering the correlation characteristics of noise impinging on different microphone pairs, is applied to the high frequencies to suppress spatially uncorrelated noise; a single-channel Wiener post-filter is applied to the low frequencies for cancellation of spatially correlated noise. In theory, the proposed post-filter is a Wiener post-filter. In practice, experiments using multi-channel recordings were conducted, and experimental results demonstrate the usefulness and superiority of the proposed post-filter compared to other post-filters using speech quality measures and speech recognition rate. (C) 2007 Elsevier Ltd. All rights reserved.